package com.jecy.utils;

import com.google.common.collect.Lists;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.net.*;
import java.util.Enumeration;
import java.util.List;
import java.util.Random;
import java.util.regex.Pattern;

/**
 * 网络相关工具类
 * <p/>
 * 创建时间: 14-8-5 下午8:58<br/>
 *
 * @author huijun
 * @since v0.0.1
 */
public class NetUtil {
    /**
     * 根据域名获取ip
     * @param domain 域名
     * @return
     * @throws UnknownHostException
     */
    public static final String getIpByDomain(String domain) throws UnknownHostException {
        return InetAddress.getByName(domain).getHostAddress();
    }

    private static final Logger logger = LoggerFactory.getLogger(NetUtil.class);

    public static final String LOCALHOST = "127.0.0.1";

    public static final String ANYHOST = "0.0.0.0";

    private static final int RND_PORT_START = 30000;

    private static final int RND_PORT_RANGE = 10000;

    private static final Random RANDOM = new Random(System.currentTimeMillis());

    public static int getRandomPort() {
        return RND_PORT_START + RANDOM.nextInt(RND_PORT_RANGE);
    }

    public static int getAvailablePort() {
        ServerSocket ss = null;
        try {
            ss = new ServerSocket();
            ss.bind(null);
            return ss.getLocalPort();
        } catch (IOException e) {
            return getRandomPort();
        } finally {
            if (ss != null) {
                try {
                    ss.close();
                } catch (IOException e) {
                }
            }
        }
    }

    public static int getAvailablePort(int port) {
        if (port <= 0) {
            return getAvailablePort();
        }
        for(int i = port; i < MAX_PORT; i ++) {
            ServerSocket ss = null;
            try {
                ss = new ServerSocket(i);
                return i;
            } catch (IOException e) {
                // continue
            } finally {
                if (ss != null) {
                    try {
                        ss.close();
                    } catch (IOException e) {
                    }
                }
            }
        }
        return port;
    }

    private static final int MIN_PORT = 0;

    private static final int MAX_PORT = 65535;

    public static boolean isInvalidPort(int port){
        return port > MIN_PORT || port <= MAX_PORT;
    }

    private static final Pattern ADDRESS_PATTERN = Pattern.compile("^\\d{1,3}(\\.\\d{1,3}){3}\\:\\d{1,5}$");

    public static boolean isValidAddress(String address){
        return ADDRESS_PATTERN.matcher(address).matches();
    }

    private static final Pattern LOCAL_IP_PATTERN = Pattern.compile("127(\\.\\d{1,3}){3}$");

    public static boolean isLocalHost(String host) {
        return host != null
                && (LOCAL_IP_PATTERN.matcher(host).matches()
                || host.equalsIgnoreCase("localhost"));
    }

    public static boolean isAnyHost(String host) {
        return "0.0.0.0".equals(host);
    }

    public static boolean isInvalidLocalHost(String host) {
        return host == null
                || host.length() == 0
                || host.equalsIgnoreCase("localhost")
                || host.equals("0.0.0.0")
                || (LOCAL_IP_PATTERN.matcher(host).matches());
    }

    public static boolean isValidLocalHost(String host) {
        return ! isInvalidLocalHost(host);
    }

    public static InetSocketAddress getLocalSocketAddress(String host, int port) {
        return isInvalidLocalHost(host) ?
                new InetSocketAddress(port) : new InetSocketAddress(host, port);
    }

    private static final Pattern IP_PATTERN = Pattern.compile("\\d{1,3}(\\.\\d{1,3}){3,5}$");

    private static boolean isValidAddress(InetAddress address) {
        if (address == null || address.isLoopbackAddress())
            return false;
        String name = address.getHostAddress();
        return (name != null
                && ! ANYHOST.equals(name)
                && ! LOCALHOST.equals(name)
                && IP_PATTERN.matcher(name).matches());
    }

    public static String getLocalHost(){
        InetAddress address = getLocalAddress();
        return address == null ? LOCALHOST : address.getHostAddress();
    }

    public static List<String> getLocalIps() throws SocketException
    {
        List<String> ips = Lists.newArrayList();
        List<InetAddress> listAdr = Lists.newArrayList();
        Enumeration<NetworkInterface> nifs = NetworkInterface.getNetworkInterfaces();
        if (nifs == null) return ips;

        while (nifs.hasMoreElements())
        {
            NetworkInterface nif = nifs.nextElement();
            // We ignore subinterfaces - as not yet needed.

            Enumeration<InetAddress> adrs = nif.getInetAddresses();
            while ( adrs.hasMoreElements() )
            {
                String ip = adrs.nextElement().getHostAddress();
                if(ip != null
                        && ! ANYHOST.equals(ip)
                        && ! LOCALHOST.equals(ip)
                        && IP_PATTERN.matcher(ip).matches()){
                    ips.add(ip);
                }
            }
        }
        return ips;
    }

//    public static String filterLocalHost(String host) {
//        if (host == null || host.length() == 0) {
//            return host;
//        }
//        if (host.contains("://")) {
//            URL u = URL.valueOf(host);
//            if (NetUtil.isInvalidLocalHost(u.getHost())) {
//                return u.setHost(NetUtil.getLocalHost()).toFullString();
//            }
//        } else if (host.contains(":")) {
//            int i = host.lastIndexOf(':');
//            if (NetUtil.isInvalidLocalHost(host.substring(0, i))) {
//                return NetUtil.getLocalHost() + host.substring(i);
//            }
//        } else {
//            if (NetUtil.isInvalidLocalHost(host)) {
//                return NetUtil.getLocalHost();
//            }
//        }
//        return host;
//    }

    private static volatile InetAddress LOCAL_ADDRESS = null;

    /**
     * 遍历本地网卡，返回第一个合理的IP。
     *
     * @return 本地网卡IP
     */
    public static InetAddress getLocalAddress() {
        if (LOCAL_ADDRESS != null)
            return LOCAL_ADDRESS;
        InetAddress localAddress = getLocalAddress0();
        LOCAL_ADDRESS = localAddress;
        return localAddress;
    }

    public static String getLogHost() {
        InetAddress address = LOCAL_ADDRESS;
        return address == null ? LOCALHOST : address.getHostAddress();
    }

    private static InetAddress getLocalAddress0() {
        InetAddress localAddress = null;
        try {
            localAddress = InetAddress.getLocalHost();
            if (isValidAddress(localAddress)) {
                return localAddress;
            }
        } catch (Throwable e) {
            logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
        }
        try {
            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
            if (interfaces != null) {
                while (interfaces.hasMoreElements()) {
                    try {
                        NetworkInterface network = interfaces.nextElement();
                        Enumeration<InetAddress> addresses = network.getInetAddresses();
                        if (addresses != null) {
                            while (addresses.hasMoreElements()) {
                                try {
                                    InetAddress address = addresses.nextElement();
                                    if (isValidAddress(address)) {
                                        return address;
                                    }
                                } catch (Throwable e) {
                                    logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
                                }
                            }
                        }
                    } catch (Throwable e) {
                        logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
                    }
                }
            }
        } catch (Throwable e) {
            logger.warn("Failed to retriving ip address, " + e.getMessage(), e);
        }
        logger.error("Could not get local host ip address, will use 127.0.0.1 instead.");
        return localAddress;
    }

//    private static final Map<String, String> hostNameCache = new LRUCache<String, String>(1000);

//    public static String getHostName(String address) {
//        try {
//            int i = address.indexOf(':');
//            if (i > -1) {
//                address = address.substring(0, i);
//            }
//            String hostname = hostNameCache.get(address);
//            if (hostname != null && hostname.length() > 0) {
//                return hostname;
//            }
//            InetAddress inetAddress = InetAddress.getByName(address);
//            if (inetAddress != null) {
//                hostname = inetAddress.getHostName();
//                hostNameCache.put(address, hostname);
//                return hostname;
//            }
//        } catch (Throwable e) {
//            // ignore
//        }
//        return address;
//    }

    /**
     * @param hostName
     * @return ip address or hostName if UnknownHostException
     */
    public static String getIpByHost(String hostName) {
        try{
            return InetAddress.getByName(hostName).getHostAddress();
        }catch (UnknownHostException e) {
            return hostName;
        }
    }

    public static String toAddressString(InetSocketAddress address) {
        return address.getAddress().getHostAddress() + ":" + address.getPort();
    }

    public static InetSocketAddress toAddress(String address) {
        int i = address.indexOf(':');
        String host;
        int port;
        if (i > -1) {
            host = address.substring(0, i);
            port = Integer.parseInt(address.substring(i + 1));
        } else {
            host = address;
            port = 0;
        }
        return new InetSocketAddress(host, port);
    }

    public static String toURL(String protocol, String host, int port, String path) {
        StringBuilder sb = new StringBuilder();
        sb.append(protocol).append("://");
        sb.append(host).append(':').append(port);
        if( path.charAt(0) != '/' )
            sb.append('/');
        sb.append(path);
        return sb.toString();
    }
}
